Lightning or surge arresters are typically connected to power lines to carry electrical surge currents to ground, and thus, prevent damage to the lines and equipment connected thereto. Arresters offer high resistance to normal voltage across power lines, yet offer very low resistance to surge currents produced by sudden high voltage conditions caused, for example, by lightning strikes. After the surge, the voltage should drop and the arrester should then normally return to a high resistance state. However, upon arrester malfunction or failure, the high resistance state is not resumed, and the arrester continues to provide an electrical path from the power line to ground. Ultimately, the line will fail due to a short circuit condition or breakdown of the distribution transformers, and the arrester will requirement replacement.
To avoid line failure, disconnectors are commonly used in conjunction with arresters to separate a malfunctioning arrester from the circuit and provide visual indication of arrester failure. Conventional disconnectors have an explosive charge to destroy the circuit path and physically separate the electrical terminals.
Examples of prior disconnector devices are disclosed in McMorris U.S. Pat. No. 2,305,436; Smith U.S. Pat. No. 2,305,394; McFarlin U.S. Pat. No. 2,504,438; Stoelting U.S. Pat. Nos. 2,551,858 and 2,607,869; Hedlund et al. U.S. Pat. No. 2,820,869, MacRae U.S. Pat. No. 2,957,967; Hicks U.S. Pat. No. 2,989,608; Robinson U.S. Pat. No. 3,017,539; Riley U.S. Pat. No. 3,100,246; Snell, Jr. U.S. Pat. No. 3,239,631; Carothers et al. U.S. Pat. No. 3,291,937; Carothers U.S. Pat. No. 3,588,773; Irie et al. U.S. Pat. No. 3,668,458; Carothers et al. U.S. Pat. Nos. 3,679,938 and 3,702,419; Cunningham et al. 3,869,650; Stetson U.S. Pat. No. 4,204,238; Barnes U.S. Pat. No. 4,479,105; Sykes et al. U.S. Pat. No. 4,503,414; and Cunningham U.S. Pat. No. 4,734,823.